Uptake of Indosol Dark-blue GL dye from aqueous solution by water hyacinth roots powder: adsorption and desorption study     

Md. M. R. Khan  M. Z. B. Mukhlish  M. S. I. Mazumder  K. Ferdous  D. M. R. Prasad  Z. Hassan 《International Journal of Environmental Science and Technology》2014,11(4):1027-1034

Adsorption characteristics of water hyacinth roots powder for the removal of Indosol Dark-blue GL dye were investigated in batch mode. Operating variables, such as initial solution pH, presence of detergent, adsorbent dosage, initial concentration and contact time, were studied. The results showed that the adsorption of dye increased with increasing the initial concentration and contact time. The adsorption is highly pH dependent and adsorption capacity increased with decrease in pH. Kinetic study revealed that the uptake of Indosol Dark-blue GL was very rapid within the first 15 min and equilibrium time was independent of initial concentration. Batch equilibrium experiments were carried out at different pH and found that equilibrium data fitted well to Langmuir isotherm model. The maximum sorption capacity of the adsorbent was found as 86 mg g^?1 at pH 3 which reduced to 64 mg g^?1 at pH 5. The presence of detergent reduced the sorption capacity of the adsorbent significantly. Using equilibrium and kinetic data, the forward and backward rate constants were determined from the unified approach model. Desorption study revealed that the dye can be recovered by swing the pH from low to high.  相似文献   

Recurring emergence of the mud islands on shelf of the Arabian Sea along the Makran coast of Pakistan – Historical perspective using remote sensing techniques     

Akhtar M. Kassi  Huseyin Bayraktar  Shuhab D. Khan  Aimal K. Kasi 《Journal of the Geological Society of India》2017,90(2):201-208

Recurring emergences of mud islands on shelf of the Arabian Sea, along the Makran coast of Pakistan are now known to be submarine mud volcanoes. They are expressions of enhanced extrusions of fluidized mud and gases coupled with compressional tectonics in convergent margin settings. Since 1945 the Malan island has emerged four times, and some other mud islands have also been emerging repeatedly, at their own positions.The first known emergence, during November 1945, was concurrent with an earthquake of magnitude 8.0 (M8.0), the 2^nd and 3^rd emergences, in March 1999 and November 2010 respectively, were not related apparently with earthquakes. The 4^th emergence concurred with the Awaran earthquake (M7.7) of 24th September 2013. Landsat images of March 1999 and November 2010 emergences indicate appearance of round-shaped island of 4.4 and 5.2 hectare area, followed by erosion and disappearance. The island was composed of mud breccias and circular vents spewing mud slurry and methane gas.The emergence of Malan island, in March 1999 and November 2010 was compared with earthquake data before and after the emergences. The earthquakes data, two years before March 1999 and November 2010 emergences and two years afterwards, shows correlation with both small and large earthquakes, prior to the emergence, in the radius of over 400 km. It is proposed that mud islands develop in response to the episodes of enhanced mud extrusion, which inturn are related with the enhanced compressional and/or seismic events. These events are followed by periods of relative quiescence characterized by normal activity of mud extrusion and marine erosion.  相似文献   

Spatial and temporal variations of physicochemical and heavy metal pollution in Ramganga River—a tributary of River Ganges,India     

Mohd Yawar Ali Khan  Khalid Muzamil Gani  Govind Joseph Chakrapani 《Environmental Earth Sciences》2017,76(5):231

The River Ganges being the most sacred river and lifeline to millions of Indians in serving their water requirements is facing excessive threat of pollution. Under various river management and conservation strategies for its protection, the assessment of water quality of its main tributary Ramganga River is lacking. This study focuses on assessment of physicochemical and heavy metal pollution of the Ramganga River by application of multivariate statistical techniques. Sampling of Ramganga River at sixteen sampling sites was carried out in three seasons (summer, monsoon and winter) of 2014. The collected water samples were analyzed for physicochemical parameters and heavy metals. Results from cluster analysis (CA) of the data divided the whole stretch of the river into three clusters as elevation from 1304 to 259 m as less polluted, from 207 to 154 m as moderately polluted and from elevation 154 to 139 m as high-polluted stretches with anthropogenic as main sources of pollution in high-polluted stretch. Principal component analysis of the seasonal dataset resulted in three significant principal components (PC) in each season explaining 72–8% of total variance with strong loadings (>0.75) of PC1 on fluoride (F^?), chloride (Cl^?), sodium (Na⁺), calcium (Ca²⁺), magnesium (Mg²⁺), bicarbonate (HCO₃ ^?), total dissolved solids and electrical conductivity. Temporal variation by one-way ANOVA (Analysis of Variance) showed significant seasonal variation was in the pH, chemical oxygen demand, biochemical oxygen demand, turbidity, HCO₃ ^?, F^?, Zn, cadmium (Cd) and Mn (p < 0.05). Turbidity showed approximately a twofold increase in monsoon season due to rainfall in the catchment area and subsequent flow of runoff into the river. Concentration of HCO₃ ^?, F^? and pH also showed similar increase in monsoon. The concentration of Zn, Cd and Mn showed an increasing trend in summers compared to monsoon and winter season due to dilution effect in the monsoon season and its lasting effect in winters.  相似文献   

Petrography,provenance, diaganesis and depositional environment of Murree Formation in Jhelum Valley,Sub Himalayas,Azad Jammu and Kashmir,Pakistan     

Muhammad Zaheer  Muhammad Sabir Khan  Muhammad Saleem Mughal  Noman Abbasi 《Arabian Journal of Geosciences》2017,10(23):514

The clastic sediments of the Murree Formation of Miocene age are exposed in Jhelum valley areas of Azad Jammu and Kashmir Pakistan. Field observations revealed the cyclic deposition in the Murree Formation. The sandstone, siltstone, and shale constitute a single cycle within the formation. This single unit is divided into five different lithofacies which constitute the Bouma sequence in the Murree Formation. The Murree Formation shows faulted contacts with Panjal Formation and Nagri Formation in the study area. The modal mineralogy data obtained from the petrography of sandstone indicates that sandstone is litharenite and lithic greywacke. The mineralogical and textural data suggests that sandstone is compositionally mature and poorly to moderately sorted. The dominantly angular to sub angular quartz grains show nearness of the source area. Fractured and sutured quartz grain reveals tectonodiagentic changes that occurred in Murree Formation. The sandstone experienced diagenetic changes. The pressure solution and cementation reduced the primary porosity of sandstone. However, alteration of feldspar and fractures in grains have produced secondary porosity. The X-ray diffraction (XRD) of the shale samples indicates that shale of the Murree Formation is argillaceous and dominated by illite clay mineral. The illite crystallinity values indicate very low grade metamorphism of Murree Formation in core of Hazara Kashmir Syntaxis. The petrographic data suggests that the provenance of sandstone is recycled orogen. Quartz is of igneous and metamorphic origin. Feldspar (albite and microcline) composition suggests its derivation from acidic igneous rocks. The rock fragments of volcanics, slate, phyllite, and schist suggest igneous and metamorphic provenance. The petrographic data suggests that at the time of deposition of Murree Formation, igneous and low grade metamorphic rocks were exposed. However, presence of some clasts of carbonates indicates that sedimentary rocks were also exposed in the source region. The quartz content and clay minerals in the shale revealed that source region was igneous and metamorphic rocks. Cyclic deposition, lithofacies, and various sedimentary structures like cross bedding, ripple marks, and calcite concretions suggest that deposition of Murree Formation occurred in fluviatile environment by meandering river system having decreasing turbidity current.  相似文献   

湖泊碎屑岩沙坝成因机制及构型表征研究进展^*          下载免费PDF全文

邱隆伟  李欣  杨勇强  董道涛  伏健  文旭  Danish Khan 《古地理学报》1999,24(2):191-209

湖泊碎屑岩沙坝因波浪和沿岸流的反复冲刷,成熟度较高,显示出巨大的油气勘探潜力,已成为隐蔽油气藏勘探的重点。作者在大量文献调研的基础上,总结了近年来前人在滩坝定义、沉积特征、主控因素、成因机制及内部构型研究中的重要进展,在此基础上提出了沙坝演化阶段及沉积构型的新认识。结果表明,沙坝完整的演化历程主要包括4个阶段,分别是弱波浪作用阶段、动荡水流—冲洗回流阶段、风成阶段及沼泽化阶段。影响沙坝发育的控制因素多样,其中物源和风场是沙坝发育的根本因素,两者分别影响了沙坝发育的物质来源和能量供给;而风场所决定的水动力是影响沙坝储集体发育的最直接因素;构造运动和层序演化则控制沙坝的分布位置及保存程度;各因素综合作用决定了坝的形态、发育规模及保存状况。依据前人构型理论,将沙坝构型按照正序方案依次划分为6级,对构型表征方法和沙坝3~5级构型定量表征进行了初步探索,以期为滩坝砂体勘探开发提供理论和实践支持。  相似文献   

Scenario-based seismic hazard analysis using spectral element method in northeastern Pakistan     

Khan  Saad  van der Meijde  Mark  van der Werff  Harald  Shafique  Muhammad 《Natural Hazards》2020,103(2):2131-2144

Natural Hazards - Seismic hazard analysis is carried out in this study by estimating ground motion for hypothetical earthquakes in the area of Muzaffarabad, Pakistan, with the MT solution of the...  相似文献   

Hydro-geochemical evaluation of groundwater with studies on water quality index and suitability for drinking in Sagardari,Jashore          下载免费PDF全文

Ahmed Mohammad Tofayal  Monir Minhaj Uddin  Hasan Md Yeasir  Rahman Md Mominur  Rifat Md Shamiul Islam  Islam Md Naim  Khan Abu Shamim  Rahman Md Mizanur  Islam Md Shajidul 《地下水科学与工程》2020,8(3):259-273

Sagardari union is facing groundwater crisis because of contaminations from agriculture and urban sewage, which bring a considerable change in water quality. In view of this, hydro-chemical analyses were undertaken on 35 groundwater samples and the following hydro-geochemical parameters, pH, total dissolved solids (TDS), total hardness (TH), electrical conductivity (EC), cations and anions, were analyzed. From the analytical results, it is found that pH value was lower than WHO drinking water standard and the middle-downstream portions of the investigation region show higher EC. The piper plot indicates that the groundwater in Sagardari falls in the categories of NaClHCO₃ hydro-chemical facies. Higher TH in groundwater was detected, but still in an acceptable range. In addition, salinity and arsenic ratio are higher and moderately higher, respectively. The spatial distribution of Groundwater Quality Index (GWQI) was determined by geo-statistical modelling of Sagardari union. The study provides information and supports the administration which to make better groundwater utilization and quality control in the Sagardari union.  相似文献   

A wavelet based approach for combining the outputs of different rainfall–runoff models     

Muhammad?ShoaibEmail author  Asaad?Y.?Shamseldin  Sher?Khan  Mudasser?Muneer?Khan  Zahid?Mahmood?Khan  Bruce?W.?Melville 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(1):155-168

The rainfall–runoff modelling being a stochastic process in nature is dependent on various climatological variables and catchment characteristics and therefore numerous hydrological models have been developed to simulate this complex process. One approach to modelling this complex non-linear rainfall–runoff process is to combine the outputs of various models to get more accurate and reliable results. This multi-model combination approach relies on the fact that various models capture different features of the data, and hence combination of these features would yield better result. This study for the first time presented a novel wavelet based combination approach for estimating combined runoff The simulated daily output (Runoff) of five selected conventional rainfall–runoff models from seven different catchments located in different parts of the world was used in current study for estimating combined runoff for each time period. Five selected rainfall–runoff models used in this study included four data driven models, namely, the simple linear model, the linear perturbation model, the linearly varying variable gain factor model, the constrained linear systems with a single threshold and one conceptual model, namely, the soil moisture accounting and routing model. The multilayer perceptron neural network method was used to develop combined wavelet coupled models to evaluate the effect of wavelet transformation (WT). The performance of the developed wavelet coupled combination models was compared with their counterpart simple combination models developed without WT. It was concluded that the presented wavelet coupled combination approach outperformed the existing approaches of combining different models without applying input WT. The study also recommended that different models in a combination approach should be selected on the basis of their individual performance.  相似文献   

Wind-induced hydrodynamic changes impact on sediment resuspension for large,shallow Lake Taihu,China     

Abdul Jalil  Yiping Li  Ke Zhang  Xiaomeng Gao  Wencai Wang  Hafiz Osama Sarwar Khan  Baozhu Pan  Salar Ali  Kumud Acharya 《国际泥沙研究》2019,34(3):205-215

The internal sediment release is a key factor controlling eutrophication processes in large,shallow lakes.Sediment resuspension is associated with the wave and current induced shear stress in large,shallow lakes.The current study investigated the wind field impacts on sediment resuspension from the bottom at Meiliang Bay of large,shallow Lake Taihu.The impacts of the wind field on the wave,current,and wave-current combined shear stresses were calculated.The critical wind speed range was 4–6 m/s after which wave and current shear stress started to increase abruptly,and onshore wind directions were found to be mainly responsible for greater shear stress at the bottom of Lake Taihu.A second order polynomial fitting correlation was found between wave(R^2 0.4756)and current(R^2 0.4466)shear stresses with wind speed.Wave shear stress accounted for 92.5% of the total shear stress at Meiliang Bay.The critical wave shear stress and critical total shear stress were 0.13 N/m^2 for sediment resuspension whereas the current shear stress was 0.019 N/m^2 after which suspended sediment concentrations(SSC)increased abruptly.A second order polynomial fitting correlation was found between wave(R^2 0.739),current(R^2 0.6264),and total shear stress(R^2 0.7394)with SSC concentrations at Meiliang Bay of Lake Taihu.The sediment resuspension rate was 120 to 738 g/m^2/d during 4–6 m/s onshore winds while offshore winds contributed ≥ 200 g/m^2/d.The study results reveal the driving mechanism for understanding the role of the wind field in sediment resuspension while considering wind speed and direction as control parameters to define wave and current shear stresses.  相似文献   

Geophysical Investigation of Fresh‐Saline Water Interface: A Case Study from South Punjab,Pakistan          下载免费PDF全文

Muhammad Hasan  Yanjun Shang  Gulraiz Akhter  Majid Khan 《Ground water》2017,55(6):841-856

The importance of the study of fresh‐saline water incursion cannot be over‐emphasized. Borehole techniques have been widely used, but they are quite expensive, intrusive, and time consuming. The electrical resistivity method has proved very successful in groundwater assessment. This advanced technique uses the calculation of Dar‐Zarrouk (D‐Z) parameters, namely longitudinal unit conductance, transverse unit resistance, and longitudinal resistivity has been employed by using 50 vertical electrical sounding points to assess the groundwater and delineate the fresh‐saline water interface over 1045 km² area of Khanewal in Southern Punjab of Pakistan. The x‐y plots and maps of D‐Z parameters were produced to establish a decipherable vision for the occurrence and distribution of different water‐bearing formations of fresh‐saline water aquifers through a complicated situation of intermixing of different resistivity ranges for fresh‐saline water bodies. This technique is useful to reduce the ambiguity produced by the process of equivalence and suppression which cause intermixing in differentiating fresh, brackish, and saline aquifers during interpretation. The fresh‐saline water interface is correlated very well with the previous studies of water quality analysis carried out in Khanewal area. The results suggest that the D‐Z parameters are useful for demarcating different aquifer zones. The behavior and pattern of D‐Z parameters with respect to occurrence and distribution of different water‐bearing formations were effectively identified and delineated in the study area.  相似文献